The magnetic storage industry has been increasing the density storage capacity of hard drives with various technological advancements. Such advancements include perpendicular data storage as well as the use of magnetoresistive (MR) heads for pickup of data from the disk. An MR head includes an MR element made out of a material which changes electrical resistance depending on the strength of the magnetic field in which it lies. MR heads are known to suffer from a transient phenomenon commonly referred to as thermal asperity (TA) events. An MR head normally glides over a spinning magnetic disk close to, but not touching, the disk surface. When an MR head hits a protruding object on the disk surface, the MR element heats up rapidly and decays relatively slowly. The effect of such a transient phenomenon is a transient change in the baseline of the read-back signal coming from the MR head. See FIG. 1. This transient change contains a substantial low-frequency component and causes loss of read-back data. The extent of the read-back data lost to TA events depends on the robustness of the data detection system and the rate at which TA events occur.
In perpendicular recording systems, the rate of TA events is generally greater than in other data recording systems such as longitudinal recording systems. Perpendicular recording systems are a recent advancement in the data storage industry that potentially may provide much higher data storage densities than conventional recording systems. However, perpendicular recording systems are typically subject to an increased rate of TA events due to the relative close proximity of the recording head to the magnetic media that is typically required in this type of recording system. In addition, due to the closer relative distance between the recording head and the media, the heating of the recording head from the TA event is generally elevated over longitudinal recording systems. The increased heating translates into a transient of increased duration and amplitude in the output signal of the recording head. Therefore, the recording head signal of perpendicular recording systems typically includes both an increased rate of TA events and TA events having a longer duration. A data detection system for a perpendicular recording system without a transient detection and suppression circuit may lose a large amount of data, even to the point that the error correcting code used in the recording system cannot regenerate the user data.